After a long and colorful life working in munitions and getting entangled in the Spanish Civil War, the Manhattan Project, and other definitive events of the 20th century, Allan Karlsson finds himself stuck in a nursing home. Determined to escape on his 100th birthday, he leaps out of a window and onto the nearest bus, kicking off an unexpected journey involving, among other surprises, a suitcase stuffed with cash, some wicked criminals, and an elephant named Sonya.